Pediatric occipitocervical fixation: radiographic criteria, surgical technique, and clinical outcomes based on experience of a single surgeon

Developing consensus for the management of pediatric cervical spine disorders and stabilization: a modified Delphi study

OBJECTIVE

Cervical spine disorders in children are relatively uncommon; therefore, paradigms for surgical and nonsurgical clinical management are not well established. The purpose of this study was to bring together an international, multidisciplinary group of pediatric cervical spine experts to build consensus via a modified Delphi approach regarding the clinical management of children with cervical spine disorders and those undergoing cervical spine stabilization surgery.

METHODS

A modified Delphi method was used to identify consensus statements for the management of children with cervical spine disorders requiring stabilization. A survey of current practices, supplemented by a literature review, was electronically distributed to 17 neurosurgeons and orthopedic surgeons experienced with the clinical management of pediatric cervical spine disorders. Subsequently, 52 summary statements were formulated and distributed to the group. Statements that reached near consensus or that were of particular interest were then discussed during an in-person meeting to attain further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).

RESULTS

Forty-five consensus-driven statements were identified, with all participants willing to incorporate them into their practice. For children with cervical spine disorders and/or stabilization, consensus statements were divided into the following categories: A) preoperative planning (12 statements); B) radiographic thresholds of instability (4); C) intraoperative/perioperative management (15); D) postoperative care (11); and E) nonoperative management (3). Several important statements reaching consensus included the following recommendations: 1) to obtain pre-positioning baseline signals with intraoperative neuromonitoring; 2) to use rigid instrumentation when technically feasible; 3) to provide postoperative external immobilization for 6-12 weeks with a rigid cervical collar rather than halo vest immobilization; and 4) to continue clinical postoperative follow-up at least until anatomical cervical spine maturity was reached. In addition, preoperative radiographic thresholds for instability that reached consensus included the following: 1) translational motion ≥ 5 mm at C1-2 (excluding patients with Down syndrome) or ≥ 4 mm in the subaxial spine; 2) dynamic angulation in the subaxial spine ≥ 10°; and 3) abnormal motion and T2 signal change on MRI seen at the same level.

CONCLUSIONS

In this study, the authors have demonstrated that a multidisciplinary, international group of pediatric cervical spine experts was able to reach consensus on 45 statements regarding the management of pediatric cervical spine disorders and stabilization. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

Pediatric craniocervical fusion: predictors of surgical outcomes, risk of recurrence, and re-operation

PURPOSE

Craniocervical junction abnormalities include a wide variety of disorders and can be classified into congenital or acquired. This study aimed to review the surgical outcome of pediatric patients who underwent craniocervical and/or atlantoaxial fusion.

METHODS

This is a retrospective cohort study including all pediatric patients (≤ 18 years) who underwent craniocervical and/or atlantoaxial fusion between 2009 and 2019 at quaternary medical city.

RESULTS

A total of 25 patients met our criteria and were included in the study. The mean age was 9 years (range: 1-17 years). There was a slight female preponderance (N = 13; 52%). Most patients (N = 16; 64%) had non-trauamatic/chronic causes of craniocervical instability. Most patients presented with neck pain and/or stiffness (N = 14; 56%). Successful fusion of the craniocervical junction was achieved in most patients (N = 21; 84%). Intraoperative complications were encountered in 12% (N = 3) of the patients. Early postoperative complications were observed in five patients (20%). Five patients (20%) experienced long-term complications. Revision was needed in two patients (8%). Older age was significantly associated with higher fusion success rates (p = 0.003). The need for revision surgery rates was significantly higher among younger age group (3.75 ± 2, p = 0.01).

CONCLUSIONS

The study demonstrates the surgical outcome of craniocervical and/or atlantoaxial fusion in pediatric patients. Successful fusion of the craniocervical junction was achieved in most patients. Significant association was found between older age and successful fusion, and between younger age and need for revision surgery.

Management of pediatric clival chordoma with extension to the craniocervical junction and occipito-cervical fusion: illustrative case

BACKGROUND

Chordomas are rare malignant neoplasms that develop from the primitive notochord with < 5% of the tumors occurring in pediatric patients younger than the age of 20. Of these pediatric chordomas, those affecting the craniocervical junction (C1–C2) are even more rare; therefore, parameters for surgical management of these pediatric tumors are not well characterized.

OBSERVATIONS

In this case, a 3-year-old male was found to have a clival chordoma on imaging with extension to the craniocervical junction resulting in spinal cord compression. Endoscopic-assisted transoral transclival approach for clival tumor resection was performed first. As a second stage, the patient underwent a left-sided far lateral craniotomy and cervical laminectomy for resection of the skull base chordoma and instrumented fusion of the occiput to C3. He made excellent improvements in strength and dexterity during rehab and was discharged after 3 weeks.

LESSONS

In pediatric patients with chordoma with extension to the craniocervical junction and spinal cord compression, decompression with additional occipito-cervical fusion appears to offer a good clinical outcome. Fusion performed as a separate surgery before or at the same time as the initial tumor resection surgery may lead to better outcomes.

Transarticular Screw Fixation in the Treatment of Severe C1-C2 Dislocation: A Case Series Report

Background

To aim of the present paper was to evaluate the results of halo traction and transarticular screw fixation combined with bone autoplasty in patients with severe atlantoaxial dislocation.

Case presentation

This is a retrospective study of severe cases of atlantoaxial dislocation in nine patients (six men and three women) treated with preoperative halo traction and posterior C1–C2 transarticular screw fixation combined with bone autoplasty from June 2006 to June 2011 at the Saint Paul Hospital (Hanoi). The mean age of patients was 37.48 ± 13.753 years (range, 26–50 years). The possibility of fixing dislocation using a halo apparatus was investigated through a series of preoperative halo corrections performed within a span of 1–2 weeks. For transarticular screw fixation, two transarticular screws were used that were positioned according to the Magerl technique. For bone autoplasty, an iliac crest bone graft approximately 3 × 2 cm in size was used. The postoperative assessment of clinical improvement was performed using the neck disability index (NDI), the American Spinal Injury Association (ASIA) impairment scale, and the visual analog scale (VAS) measurement instruments, through the gradation of atlantoaxial dislocation, and via the clivoaxial angle(CAA) index and the space available for cord (SAC) index after 6 months. The image diagnosis demonstrates that all the cases of atlantoaxial dislocations are unstable and correspond to the Fielding and Hawkins type III dislocation. Eight patients underwent complete reduction using the halo fixation device. In one patient, the C1–C2 displacement was manually reduced during surgery. CT scanning revealed that the accuracy of screw placement was 94.4%. The bone fusion rate was 100% after 6 months. Based on the ASIA impairment scale, the preoperative examination of patients revealed grade C injuries in seven patients and grade D injuries in two patients. After surgery, all patients had grade D injuries. Six months after surgery, four patients had moderate self‐reported neck disability (30%–48%) and five patients reported mild disability (10%–28%); that is, the patient perception of the neck problem improved. In the postoperative phase, all patients showed an improvement in VAS pain scores and the SAC score returned to the normal range in all patients. The CAA returned to normal in only seven patients; in the other two patients, the CAA returned to a value that was close to normal (145° and 149°).

Conclusion

Through halo traction combined with transarticular screw fixation and bone autoplasty, noticeable postoperative improvements were attained based on the clinical scores for NDI, ASIA, and VAS, as well as SAC and CAA.

Posterior Direct Reduction of Lateral Atlantoaxial Joints for Rigid Pediatric Atlantoaxial Subluxation: A Fulcrum Lever Technique

STUDY DESIGN

Clinical case series.

OBJECTIVE

To present a surgical technique and results of posterior direct reduction of lateral atlantoaxial joints for rigid pediatric atlantoaxial subluxation (AAS) using a fulcrum lever technique.

SUMMARY OF BACKGROUND DATA

The surgical treatment of pediatric rigid AAS is still technically challenging. Several factors contribute to the surgical difficulty, such as small vertebrae, incomplete bone formation, dysplasia, the difficulty of reduction and external fixation are considered as a surgical daunting challenge. Herein, the surgical technique of posterior direct reduction of lateral atlantoaxial joints for rigid pediatric AAS using a fulcrum lever technique is presented.

METHODS

This retrospective study included 10 pediatric patients with rigid AAS who underwent posterior direct reduction of bilateral C1/2 facet joints via a fulcrum lever technique. The indication for surgery was the presence of neurological symptoms and spinal cord atrophy with an intramedullary high signal at the C1 level on T2-weighted magnetic resonance (MR) images. The surgical procedure consisted of three steps: (1) opening and distraction of the C1/2 facet joints and placement of tricortical bone as a spacer and fulcrum; (2) placement of C1 and C2 screws; and finally, (3) compression between the C1 posterior arch and C2 lamina and constructing C1/2 fusion. All patients underwent the neurological and radiological evaluations before and after surgery.

RESULTS

Eight of 10 patients demonstrated genetic disorders, either Down syndrome or chondrodysplasia punctate. Besides, all cases documented congenital anomaly of the odontoid process. Bilateral C1 lateral mass screws were successfully placed in all cases. No evidence of postoperative neurovascular complications. Radiological evaluation showed the corrections and bony fusions of C1/2 facet joint in all cases.

CONCLUSION

The fulcrum lever technique for rigid pediatric AAS can be one of the effective surgical solutions to this challenging pediatric spinal disorder.

LEVEL OF EVIDENCE

4.

Atlanto-Occipital Transarticular Screw Fixation for the Treatment of Traumatic Occipitocervical Instability in the Pediatric Population

BACKGROUND

Atlanto-occipital transarticular screw fixation (AOTSF) has rarely been reported for fixation of the craniovertebral junction (CVJ).

METHODS

A retrospective chart review of all pediatric patients (less than 18 years of age) with an attempt of AOTSF for fixation of traumatic CVJ instability was conducted.

RESULTS

A total of 4 patients (2 boys and 2 girls; ages 2, 3, 5, and 8 years) who suffered from acute traumatic CVJ instability managed during 2007-2018 underwent an attempted AOTSF. In 2 patients, this method was technically successful. In the other 2 instances, we were not able to engage the screw into the occipital condyle. These were converted to standard occipital plate, rod, and screw fixation. All were placed in a halo subsequently for a minimum of 3 months. Three patients were fused at last follow-up (range, 17-48 months). One patient after successful AOTSF did not fuse. There were no surgical complications or revision procedures.

CONCLUSIONS

AOTSF was feasible in half of pediatric patients suffering from traumatic CVJ instability. Therefore, intraoperative salvage options and strategies should be on hand readily. In the pediatric population, where bony anatomy may pose challenges to fixation, this technique may offer a viable first-line option in selected cases, despite the overall modest success rate.

Surgical Management of Spinal Disorders in People with Mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are a group of inherited, multisystem, lysosomal storage disorders involving specific lysosomal enzyme deficiencies that result in the accumulation of glycosaminoglycans (GAG) secondary to insufficient degradation within cell lysosomes. GAG accumulation affects both primary bone formation and secondary bone growth, resulting in growth impairment. Typical spinal manifestations in MPS are atlantoaxial instability, thoracolumbar kyphosis/scoliosis, and cervical/lumbar spinal canal stenosis. Spinal disorders and their severity depend on the MPS type and may be related to disease activity. Enzyme replacement therapy or hematopoietic stem cell transplantation has advantages regarding soft tissues; however, these therapeutic modalities are not effective for bone or cartilage and MPS-related bone deformity including the spine. Because spinal disorders show the most serious deterioration among patients with MPS, spinal surgeries are required although they are challenging and associated with high anesthesia-related risks. The aim of this review article is to provide the current comprehensive knowledge of representative spinal disease in MPS and its surgical management, including the related pathology, symptoms, and examinations.

Anatomical study of the ventral neurovascular structures and hypoglossal canal for the surgery of the upper cervical spine

The aim of this study is to evaluate the anatomical relationship between the bony structures and ventral neurovascular structures around craniovertebral junction (CVJ). Eleven fresh-frozen cadaveric specimens were dissected around CVJ. The anatomical relationships were evaluated between C1 bony structures (midline, lateral margin of the C1 lateral mass (LM) and C1 transverse process (TP)) and ventral neurovascular structure such as ICA and HN. Morphometric evaluation of occipital condyle was also performed. The diameter of the HN and the ICA was 2.4 ± 0.5 mm and 5.1 ± 0.2 mm. The ICA was located lateral to the C1 LM in 44.4% (ICA Group 1) and in front of lateral half of the C1 LM in 55.6% (ICA Group 2). The HN was located lateral to the C1 LM in 85% (HN Group 1) and in front of lateral half of the C1 LM in 15% (HN Group 2). HN Group 2 was significantly more common in ICA Group 2 (p < 0.05, OR = 2.00, 95% CI: 1.07-3.71). There was significant correlation between ICA and HN in terms of the distance from the midline, C1 LM and TP (r = 0.67, 0.87 and 0.76 respectively, P < 0.01). In conclusion, the HN location is related with ICA location and the medially located ICA is a risk factor of the HN located ventral to the C1 LM. These results demonstrate the vulnerability of the neurovascular structures during CVJ surgery and suggest that preoperative 3D-CTA or enhanced CT scan can be useful in guiding surgical technique.

Autogenic Rib Graft for Atlantoaxial and Occipitocervical Fixation in Pediatric Patients

Study Design

Retrospective case series.

Purpose

To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients.

Overview of Literature

Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting.

Methods

We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications.

Results

The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site.

Conclusions

Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

Spinal instrumentation in infants, children, and adolescents: a review

OBJECTIVEThe evolution of pediatric spinal instrumentation has progressed in the last 70 years since the popularization of the Harrington rod showing the feasibility of placing spinal instrumentation into the pediatric spine. Although lacking in pediatric-specific spinal instrumentation, when possible, adult instrumentation techniques and tools have been adapted for the pediatric spine. A new generation of pediatric neurosurgeons with interest in complex spine disorder has pushed the field forward, while keeping the special nuances of the growing immature spine in mind. The authors sought to review their own experience with various types of spinal instrumentation in the pediatric spine and document the state of the art for pediatric spine surgery.METHODSThe authors retrospectively reviewed patients in their practice who underwent complex spine surgery. Patient demographics, operative data, and perioperative complications were recorded. At the same time, the authors surveyed the literature for spinal instrumentation techniques that have been utilized in the pediatric spine. The authors chronicle the past and present of pediatric spinal instrumentation, and speculate about its future.RESULTSThe medical records of the first 361 patients who underwent 384 procedures involving spinal instrumentation from July 1, 2007, to May 31, 2018, were analyzed. The mean age at surgery was 12 years and 6 months (range 3 months to 21 years and 4 months). The types of spinal instrumentation utilized included occipital screws (94 cases); C1 lateral mass screws (115 cases); C2 pars/translaminar screws (143 cases); subaxial cervical lateral mass screws (95 cases); thoracic and lumbar spine traditional-trajectory and cortical-trajectory pedicle screws (234 cases); thoracic and lumbar sublaminar, subtransverse, and subcostal polyester bands (65 cases); S1 pedicle screws (103 cases); and S2 alar-iliac/iliac screws (56 cases). Complications related to spinal instrumentation included hardware-related skin breakdown (1.8%), infection (1.8%), proximal junctional kyphosis (1.0%), pseudarthroses (1.0%), screw malpositioning (0.5%), CSF leak (0.5%), hardware failure (0.5%), graft migration (0.3%), nerve root injury (0.3%), and vertebral artery injury (0.3%).CONCLUSIONSPediatric neurosurgeons with an interest in complex spine disorders in children should develop a comprehensive armamentarium of safe techniques for placing rigid and nonrigid spinal instrumentation even in the smallest of children, with low complication rates. The authors' review provides some benchmarks and outcomes for comparison, and furnishes a historical perspective of the past and future of pediatric spine surgery.

Traumatic Occipitocervical Distraction Injuries in Children: A Systematic Review

BACKGROUND

Occipitocervical distraction injuries (OCDI) in children occur on a wide spectrum of severity, and decisions about treatment suffer from a lack of rigorous guidelines and significant inter-institutional variability. While clear cases of frank atlanto-occipital dislocation (AOD) are treated with surgical stabilization, the approach for less severe cases of OCDI is not standardized. These patients require a careful assessment of both radiographic and clinical criteria, as part of a complex risk-benefit analysis, to establish whether occipitocervical fusion (OCF) is indicated. Here, we performed a systematic review of the literature that describes traumatic OCDI in children < 18 years of age.

SUMMARY

We performed a systematic review, according to PRISMA guidelines, of children < 18 years of age presenting with traumatic etiologies of OCDI. We searched PubMed to identify papers congruent with these criteria. Exclusion criteria included (1) reports on atraumatic causes of OCDI and (2) studies with insufficient clinical and radiographic details on individual patients. We identified 16 reports describing a total of 144 patients treated for pediatric traumatic OCDI. Based on the synthesis of these findings and the collective experience of the authors, we present the demographic, clinical, and radiographic factors that underlie OC instability, which we hope will serve as components of a grading system in the future. We considered various clinical and radiographic findings including: (1) the mechanism of injury, (2) the patient's age, (3) CT/CT angiography of head and neck findings and parameters, (4) MRI findings, and (5) neurological exam, for the purpose of determining the severity of the OCDI and offering treatment guidelines based on the summative risk of underlying OC instability. Key Messages: OCDI is a potentially devastating injury, especially in children. Although missing the diagnosis can have potentially catastrophic consequences, reverting to surgical fixation in less severe cases can subject children to unnecessary operative risk and permanently reduce their range of motion. After reviewing all the available reports of pediatric traumatic OCDI in the neurosurgical literature, we propose an outline of clinical and radiographic factors influencing underlying OC instability that could be incorporated into a grading scale to guide treatment. We hope this study stimulates discussion on the standardization of treatment for pediatric OCDI.

A Modified Technique for Occipitocervical Fusion Using Compressed Iliac Crest Allograft Results in a High Rate of Fusion in the Pediatric Population

BACKGROUND

In children, high rates of occipitocervical (OC) fusion have been demonstrated with the use of rigid instrumentation in combination with harvested autograft, with or without bone morphogenetic protein (BMP). Historically, the use of allograft materials demonstrated inferior OC fusion outcomes compared with autograft. However, autograft harvest harbors an increased risk of patient morbidity, and the use of BMP is costly and controversial in children. Thus, there remains a need for safer, less costly, yet efficacious techniques for OC fusion in the pediatric population.

METHODS

We retrospectively reviewed the charts of patients younger than 21 years of age who underwent OC fusion with structural allograft placement at our institution from 2010 to 2015. Data collected included age, sex, follow-up duration, fusion outcomes, and postoperative complications.

RESULTS

A total of 19 patients (8 female and 11 male) underwent OC fusion with our surgical technique. Mean age was 8.5 ± 4.3 years. Radiographic follow up data were available for 18 of 19 patients. One patient was lost to clinical follow up but had radiographic confirmation of fusion. Thus, 18 of 18 (100%) of patients with radiographic follow-up achieved successful arthrodesis as determined by computed tomography. Median duration to documented fusion was 4.5 months. Clinical follow-up was available for 17 of 19 patients and was on average 18.8 ± 13.5 months. One patient required reoperation for graft fracture 8 months after radiographic confirmation of successful fusion. There were no vertebral artery injuries or other postoperative complications.

CONCLUSIONS

We demonstrate a modified technique for OC fusion in children with unique structural allograft shaping and affixation, leading to excellent fusion outcomes at follow up. This technique obviates the need for autograft harvest or BMP, and may decrease postoperative morbidity.